Split Core Hockey Stick Blade

ABSTRACT

A composite hockey stick blade having a paddle portion that includes an inner foam core overlaid, or sandwiched, with a plastic wrap. The inner foam core is formed having an upper section of a first foamed material and a lower section of a second foamed material, wherein the density of the upper foam core section is substantially less than the lower foam core section. More preferably, the upper foam core section has a density of about 3-5 pounds per cubic foot, while the lower foam core section has a density of greater than about 30 pounds per square foot. In addition, one or both of the foam core sections may be fiber reinforced. The location of the upper foam core section relative to lower foam core section within the paddle region may be varied to provide a hockey stick blade having different twisting and flexing characteristics.

TECHNICAL FIELD

The present invention relates generally to a hockey stick blade and, more particularly to, a split core hockey stick blade.

BACKGROUND OF THE INVENTION

Typical current hockey stick blades or replacement blades are generally made of a core material reinforced with one or more layers of synthetic material, such as fiberglass, carbon fiber or graphite. Traditionally, the core of the blade has been made of natural materials, such as wood or a wood laminate. Traditional wood constructions, however, are expensive to manufacture due to the cost of wood and the manufacturing processes employed. Further, wood sticks and blades are relatively heavy and have somewhat limited durability. Finally, due to variabilities relating to wood construction and manufacturing techniques, wood sticks are difficult to manufacture with consistent tolerances, and even the same model and brand of sticks and blades may have differences in terms of mechanical properties, such as stiffness and curvature.

Recently, in an attempt to decrease the weight of the stick and the blade, and to improve upon the durability and mechanical properties associated with the performance of the stick or blade, alternative core materials, such as synthetic materials reinforced with layers of fiber material, have been utilized. The fiber layers are usually made of woven filament fibers, typically soaked in a resin and glued to the surfaces of the core of the blade. Expandable fiber braids have also been used for covering the core of the blade. These composite sticks and blades have proven to have improved durability versus traditional wooden sticks and blades and have many of the mechanical attributes desired by hockey players. Further, these composite sticks and blades have less variability in terms of tolerances related to curvature and stiffness.

Nevertheless, these composite sticks and blades still have disadvantages. For example, conventional composite stick blades are formed from a uniform, relatively low density foam material. To achieve a desired overall stiffness and durability for the blade, many layers of fiber material must be added to the low density foam core. The additional layers of fiber material add weight and cost (raw material and manufacturing costs) to the stick and blade. In addition, the additional layers of fiber material affect the response of the stick, in terms of performance or mechanical characteristics, to a player while handling, passing and/or shooting a puck.

Accordingly, there is a demand for a composite blade having still further improved features.

SUMMARY OF THE INVENTION

It is therefore an advantage of the present invention to provide a composite blade for a hockey stick with improved response while handling, passing and/or shooting a puck.

It is another advantage of the present invention to provide a composite blade for a hockey stick that assists in preventing puck “flutter” that may occur when a player shoots or passes the puck.

It is a related advantage of the present invention to provide a composite blade for a hockey stick that minimizes twisting of the blade.

It is still another advantage of the present invention to provide a blade for a hockey stick that has decreased weight without adversely affecting the performance or mechanical characteristics of the blade.

In accordance with the above and the other advantages, the present invention provides a composite hockey stick blade formed as a composite structure having an inner foam core overlaid with, or sandwiched within, with a plastic wrap that provides regions of increased stiffness within the overall structure of the paddle. To achieve the regions of increased stiffness, the inner foam core is formed having an upper section of a first foamed material having a first set of mechanical characteristics and a lower section of a second foamed material having a differing set of mechanical characteristics. The inner foam core is thus considered a split foam core. Preferably, the upper foam core section consists of a substantially less dense foam material than the lower foam core section, thus the lower foam core section provides increased stiffness as compared to the upper foam core section. More preferably, the density of the upper foam core section is about 3-5 pounds per cubic foot, while the density of the lower foam core section is greater than about 30 pounds per square foot.

The location and density of the upper foam core section relative to the lower foam core section allows the flexing and twisting characteristics of the paddle portion of the hockey stick blade to be more precisely controlled and thereby provide more consistent performance. In addition, the presence of higher density foam core materials allows the thickness of the plastic wrap along the front face and rear face of the blade to be decreased without adversely affecting the performance or mechanical characteristics of the blade.

In yet another preferred embodiment of the present invention, fiber reinforcement, preferably in the formed of chopped fibers, is introduced to either the lower density upper foam core section, the higher density lower foam core section, or both the lower density upper foam core section and the higher density lower foam core section, to provide additional stiffness to the inner core material. This also allows the overall thickness of the plastic wrap applied to the front face and rear face of the blade to be decreased without adversely affecting the performance or mechanical characteristics of the blade.

These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a view of the frontside face of a blade according to one embodiment of the present invention;

FIG. 2 is a section view of FIG. 1 taken along line 2-2; and

FIG. 3 is a cross-sectional view of a two-piece mold used to form the blade of FIGS. 1-2 in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the FIG. 1, a hockey blade 10 is depicted in accordance with a preferred embodiment of the present invention. It should be understood that while the preferred blade is intended for use in the sport of ice hockey, it can also be utilized in other sports, including roller hockey and field hockey. In general, the blade 10 comprises a hosel 12, a heel section 14, and a paddle (blade portion) 16. The heel section 14 is generally located at the junction of the hosel 12 and the paddle 16. The hosel 12 includes a tenon 18, or insert, adapted to be inserted into a hollow hockey stick shaft (not shown) made of aluminum, composite or graphite. Alternatively, the hockey stick shaft can be constructed of wood or a wood laminate. It will also be understood that the hockey stick shaft can be constructed of a variety of other materials. The paddle 16 includes a front face 20 and a rear face 22 and further comprises a top edge 24, a tip region 26 and a bottom edge 28.

As best shown in FIG. 2, the blade 10 is preferably formed as a composite structure having an inner foam core 100 overlaid with, or sandwiched within, a plastic wrap 101. The plastic wrap 101 is preferably a fiber-reinforced prepreg material that includes one or more layers 102 comprising one or more plies 104 of substantially continuous fibers 106 disposed in a matrix or resin based material 108. Separate reinforcing layers 110 of the same type and quantity as plies 104 may be placed on the top edge 24 and the bottom edge 28 of the blade 10. It will be understood that the blade 10 may be formed as a replacement blade, i.e. separate from the shaft, or may alternatively be formed as a single integral unit with the shaft. Moreover, it will be understood that the inner foam core 100 may be reinforced with materials other than plastic wrap 101 in other ways well known to those of ordinary skill in the art and is not meant to be limited to the preferred embodiment.

As used herein the term “ply” 104 shall mean a group of fibers which all run in a single direction, largely parallel to one another, and which may or may not be interwoven with or stitched to one or more other groups of fibers each of which may be or may not be disposed in a different direction. A “layer” 102 shall mean one or more plies 104 that are laid down together.

The hosel 12 and the tenon 18 are preferably formed having one or more layers 197 of the plastic wrap 101 that are wrapped around a hollow cavity and may include an inner foam core 199. To form the hosel 12 and the tenon 18 with a hollow cavity, a removable silicone plug (not shown) is preferably utilized. The inner foam core 199 may be constructed of formulations of expanding syntactic or non-syntactic foam, such as polyurethane, PVC, epoxy, or any other suitable material capable of providing the needed pressure (i.e. expansion during heating) in the mold while having a suitable or desired weight or density.

In the preferred embodiments of the present invention, the inner foam core 100 is formed of two separate foam core materials, namely an upper foam core section 111 and a lower foam core section 113, that are co-cured in a prepreg process. The upper foam core section 111 is preferably formed of a less dense foam material than the lower foam core section 113. In addition, the upper foam core section 111 is preferably less stiff (has a lower indention load deflection, which measures the hardness of the foam) than the lower foam core section 113. The lower foam core section 113 is preferably located along the bottom portion of the paddle portion 16 and extends generally between the heel portion 14 and the tip region 26 along the bottom edge 28. As shown in FIG. 1, the lower foam core section 113 only extends along a portion of the bottom edge 28 such that a portion of the upper foam core section 111 extends along a portion of the bottom edge 28 nearer to the tip region 26. However, in other preferred embodiments (not shown) the lower foam core section 113 may extend along the entirety of the bottom edge 28 between the heel portion 14 and the tip region 26. Alternatively, the lower foam core section 113 can take on various configurations and extend over other parts of the paddle 16.

In one preferred embodiment, the upper foam core section 111 consists of polyvinyl chloride (“PVC”) foam having a density of between about 3-5 pounds per cubic foot, while the lower foam core section 113 consists of epoxy thermoset foam having a density of at least 30 pounds per cubic foot. The use of high density foam in the lower foam core section 113 allows the plastic wrap 101 thickness of the paddle 16, along the front face 20 and rear face 22, to be decreased to about 0.045 inches while providing a sufficiently stiff (i.e. sufficiently hard) blade 10 for use in shooting and passing a puck during the games of roller or ice hockey. More preferably, the thickness can be reduced to about 0.030 inches. The reduction in thickness of the plastic wrap 101 along the front face 20 and rear face 22 provides better impact capabilities, better flex loading, and forgiveness, without sacrificing strength or durability, over current composite blades having lower density foam cores having a plastic wrap thickness of around 0.060 inches.

However, in other preferred embodiments, the upper foam core section 111 and lower foam core section 113 may be constructed of formulations of expanding syntactic or non-syntactic foam, such as polyurethane, PVC, epoxy, or any other suitable material capable of providing the needed pressure (i.e. expansion during heating) in the mold while having a suitable or desired weight or density and IFD, with the further proviso, as above, that the upper foam core section 111 is preferably formed of a less dense, and more preferably less dense and less stiff foam material, than the lower foam core section 113. Most preferably, the lower foam core section 113 consists of any foam material having a density of at least 30 pounds per cubic foot density and sufficient stiffness to be used in a hockey stick blade.

In another preferred embodiment of the present invention, chopped reinforcing fibers 167 may be introduced to the upper foam core section 111, the lower foam core section 113, the foam core section 199, or any combination of two or more of the foam core sections 111, 113 and 199. In one preferred embodiment, milled carbon fiber is introduced at a ratio of about 5% by weight of the upper foam core section 111, the lower foam core section 113 or the foam core section 199. In yet a more preferred embodiment, milled carbon fiber ( 1/32″) is introduced at a load of 1.7% by weight to the lower foam core section 113, wherein the lower foam core section 113 is formed of a high-density epoxy material (0.55 SG). However, other reinforcing fibers may be utilized, including carbon fiber, aramid fiber, glass fiber, polyethylene fiber, ceramic fiber, boron fiber, quartz fiber, polyester fiber or any other fiber that may provide the desired strength. The chopped reinforcing fibers 167 provide additional durability and/or stiffness to respective core sections 111, 113 and 199. This in turn allows the plastic wrap 101 thickness of the paddle 16, along the front face 20 and rear face 22 to be further decreased, as described above, without a decrease in the properties of the blade.

The plastic wrap 101 is preferably a fiber-reinforced prepreg material that includes one or more layers 102 comprising one or more plies 104 of substantially continuous fibers 106 disposed in a matrix or resin based material 108.

Separate reinforcing layers 110 of the same type and quantity as plies 104 may be placed on the top edge 24 and the bottom edge 28 of the blade 10. It will be understood that the blade 10 may be formed as a replacement blade, i.e. separate from the shaft, or may alternatively be formed as a single integral unit with the shaft. Moreover, it will be understood that the inner foam core 100 may be reinforced with materials other than plastic wrap 101 in other ways well known to those of ordinary skill in the art and is not meant to be limited to the preferred embodiment.

The fibers 106 employed in plies 104, 197 may be comprised of carbon fiber, graphite fiber, aramid fiber, glass fiber, polyethylene fiber, ceramic fiber, boron fiber, quartz fiber, polyester fiber or any other fiber that may provide the desired strength. In addition, fiber may also be added to the outermost ply 104, 197 to form a decorative appearance. For example, a graphite fiber outer ply preferably constitutes the outermost ply 104 of the paddle 16 to provide an aesthetically pleasing appearance.

The matrix or resin based material 108 is preferably selected from a group of resin based materials, including thermoplastic materials such as polyetherether-ketone (“PEEK”), polyphenylene sulfide (“PPS”), polyethylene (“PE”), polypropylene urethanes (“PPU”), and nylons such as Nylon-6. The matrix or resin based material 108 may also include or be entirely composed of a thermosetting material, such as urethanes, epoxy, vinyl ester, polycyanate, and polyester.

In order to avoid manufacturing expenses relating to transferring the resin into the mold after the foam-fiber layers are inserted into the mold, the matrix material 108 employed is preferably pre-impregnated into the plies 104 prior to the uncured blade assembly being inserted into the mold and the mold being sealed. In addition, in order to avoid costs associated with the woven sleeve materials employed in contemporary composite blade constructs, it is preferable that the layers be comprised of one or more plies 104 of non-woven unidirectional fibers. Suitable materials include unidirectional carbon fiber tape pre-impregnated with epoxy, unidirectional glass fiber tape pre-impregnated with epoxy, and unidirectional aramid fiber tape pre-impregnated with epoxy.

As used herein the term “ply” 104 shall mean a group of fibers which all run in a single direction, largely parallel to one another, and which may or may not be interwoven with or stitched to one or more other groups of fibers each of which may be or may not be disposed in a different direction. A “layer” 102 shall mean one or more plies 104 that are laid down together.

The composition of the substantially continuous fibers 106, and/or the composition of the matrix or resin based material 108, of each individual ply 104 may be similar or varied in composition to their respective adjacent ply 104. Moreover, the fiber orientation of the continuous fibers 106 within an individual ply may be the same, or varied, from the orientation of the immediately adjacent ply 104. For example, the fiber orientation of adjacent plies may be parallel to one another (i.e. the fibers are oriented at a 0 degree angle relative to the next adjacent ply, forming a 0/0 orientation), perpendicular to one another (i.e. the fibers are oriented at a 90 degree angle relative to the next ply, forming a 0/90 pattern), or may be oriented at an angle between 0 and 90 degrees (for example, at a 30 degree, or 60 degree, angle relative to the adjacent ply). In these ways, the performance characteristics of hockey blade, in terms of relative stiffness and relative durability, may be varied from blade to blade, and hence stick to stick.

Referring now to FIG. 3, one preferred method for forming the blade 10 as described above in FIGS. 1-2 is illustrated.

First, a mold 175, corresponding to the shape of the blade 10, is formed having an inner surface 180 in the form of a front surface 177, a rear surface 179, a top surface 181, and a bottom surface 183 that define a cavity 185 corresponding to the outer periphery of the front face 20, the rear face 22, the top edge 24 and the bottom edge 28. The mold 175 also includes an inner surface 187 corresponding to the outer periphery of the hosel 12, and therein defines a second cavity portion 189 that is preferably open and continuous with the cavity 185. The mold preferably consists of two or more mold pieces 191, 193 that close to define the cavities 185, 189 that corresponds to the shape of the blade 10.

Next, one or more plies 104 of a plastic wrap 101, here pre-impregnated substantially continuous fibers comprising each respective face 22 or 24 of the blade 10, are placed into the mold 175 along the front surface 177 and the rear surface 179. As stated above, a graphite fiber outermost ply is preferably introduced along the front surface 177 and rear surface to provide an aesthetically pleasing outer appearance. In addition, one or more plies 197 of the pre-impregnated substantially continuous fibers are placed onto the outer surface 187 of the hosel region within the cavity region 189.

A long strip of reinforcement 110 is placed onto the bottom surface 183 of the mold and also encloses the plies 104. The reinforcement 110 preferably consists of one or more plies of the pre-impregnated substantially continuous fibers of similar composition to plies 104 and 197.

Next, the inner foam core 100 is introduced within the piles 104 of the first cavity portion 185 and optionally within the plies 197 of the second cavity portion 189. To accomplish this, the lower foam core section 113 is introduced within the plies 104 near the bottom section 183 of the first cavity portion 185. One or more additional plies 204 of the plastic wrap 101 are placed onto the top portion 233 of the lower foam core section 113. Finally, the upper foam core section 111 is introduced within the plies 104 and onto the plies 204 near the top surface 181 of the first cavity portion 185 and optionally within the plies 197 of the second cavity portion 189. Wherein chopped fiber 167 is included in any portion of the inner foam core 100, it is preferably first premixed with the material forming the respective foam core sections 111, 113, and 199 prior to introduction within the plies 104, 197. This premixing allows the chopped fiber 167 to be uniformly mixed throughout the entirety of the respective foam core section. Alternatively, the chopped fiber 167 could be introduced in such a way that it is selectively located within a portion of the respective foam core section 100, 199 to provide selected areas of reinforcement.

While the preferred embodiment shown in FIGS. 2 and 3 shows the height of the upper foam core region 111, measured from the plies 204 to the top edge 24 in a direction perpendicular to both the top edge 24 and bottom edge 28, being roughly equal in height to the height of the lower foam core region 113, measured from the plies 204 to the bottom edge 28, it should be understood by one of ordinary skill that the heights may vary from this arrangement, wherein the height of the upper foam core region 111 is greater than the height or the lower foam core region 113, or vice versa.

Finally, a second strip of the reinforcement 110 is draped over the upper foam core region 111 and plies 104 and is coupled near the top surface 181 of the mold 175.

Last, the plies 104 for the other face 20 or 22 of the blade 10 are added or coupled to the foam core 100 (the upper foam core section 111 and the lower foam core section 113) that is generally in the shape of the blade 10 illustrated in FIG. 1 to create an uncured blade assembly 200.

The mold 175 is closed using an automated press or tightened down by hand using bolts (not shown). Heat is then applied to the mold 175 sufficient to cure the inner foam core 100 (the upper foam core section 111, the lower foam core section 113) and the prepreg materials comprising the plies 104, 110, 204 and 197. The heat also causes the upper foam core 111 and the lower foam core 113 of the inner foam core 100 to each expand, therein exerting pressure on the plies 104, 110, 204 and compacting the laminate structure. The heat also causes the foam core 199 to expand against the plies 197 in the hosel 12. As one of ordinary skill will recognize, the amount of heat and time necessary to cure the respective inner foam core 100 (consisting of the upper foam core section 111 and the lower foam core section 113) and 199 is dependent upon numerous factors, including but not limited to the chemical composition of the respective upper foam core section 111 and the lower foam core section 113 and foam core 199, the thickness of the respective upper foam core section 111 and the lower foam core section 113 and foam core 199, and the pressure exerted within the mold 175. When the mold cycle is complete, the blade 10 is then removed from the mold 175 and finished to the desired appearance. The finishing process may include aesthetic aspects such as paint or polishing and also may include structural modifications such as deburring.

Accordingly, the present invention provides a composite hockey stick blade 10 having a split foam core paddle 16.

Thus, the composite blade of the present invention can be individually tailored based on a desired set of mechanical characteristics by simply preselecting the composition of the foamed material (with or without chopped fiber reinforcement 167) for the upper foam core section 111 and the lower foam core section 113 and foam section 199 and preselecting the location and amount of each respective foam core section 111, 113. For a stiffer blade having decreased stiffness at the tip region 26 end, for example, the lower foam core section 113 may extend substantially the entirety of the bottom edge from the heel section 14 to the tip region 26. Alternatively, the overall stiffness of the paddle 16 may be increased by increasing the height of the lower foam core section 113 relative to the height of the upper foam core section 111. These stiffer constructions at various locations along the paddle 16 can aid in preventing puck “flufter”, or prevent the blade from twisting, when a player shoots or passes the puck.

The split foam core paddle 16 of the present invention is ideally suited for use as a replacement blade for two-piece hockey sticks, wherein the hosel 12 is coated with glue on an outer surface and introduced within a hollow shaft of a hockey stick and heated to adhere the glue to the inner surface of the hockey stick shaft.

However, the present invention is also ideally suited for use in a one-piece hockey stick (i.e. without a replaceable hockey stick blade), wherein the hockey stick shaft is co-formed with the paddle and hosel.

In addition, while the present invention specifies an inner foam core consisting of an upper foam core section 111, and a lower foam core section 113, it is specifically contemplated that additional foam core sections having the same or differing densities and stiffness to the sections 111, 113, placed in different locations of the blade, are specifically contemplated by the present invention to provide a virtually limitless number of hockey stick blades having varying twisting and flexing characteristics. It will be understood that the inner foam core 100 can be constructed of a single material with reinforcing fibers 167 formed therein, with the reinforcing fibers disposed in greater density in the lowest portion of the blade 10 to provide the benefits of the present invention.

While particular embodiments of the invention have been shown and described, numerous variations or alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims. 

1. A hockey stick blade comprising: a hosel; a heel section coupled to said hosel; and a paddle portion coupled to said heel section, said paddle portion comprising a composite structure including an inner foam core overlaid with a plastic wrap, said inner foam core including an upper foam core section and a lower foam core section, said lower foam core section located along at least a portion of a bottom edge of said paddle portion from said heel section to a tip region, wherein said lower foam core section has a substantially higher density than said upper foam core section.
 2. The hockey stick blade of claim 1, wherein the density of said lower foam core section is at least 30 pounds per square foot.
 3. The hockey stick blade of claim 2, wherein the density of said upper foam core section between about 3 and 5 pounds per square foot.
 4. The hockey stick blade of claim 1, wherein said lower foam core section extends along the entire length of said bottom edge of said paddle portion from said heel section to said tip section.
 5. The hockey stick blade of claim 1, wherein a portion of said upper foam core section extends along a portion of said bottom edge near said tip region.
 6. The hockey stick blade of claim 1, wherein said upper foam core section comprises PVC foam having a density of between about 3-5 pounds per cubic foot and wherein said lower foam core section consists of epoxy thermoset foam having a density of at least 30 pounds per cubic foot.
 7. The hockey stick blade of claim 1, wherein the height of said upper foam core section is roughly equal to the height of said lower foam core section, wherein the height is measured along an axis of the paddle portion perpendicular to said top edge and said bottom edge of said paddle portion at a position wherein said upper foam core section is located along said top edge and wherein said lower foam core section is located along said bottom edge.
 8. The hockey stick blade of claim 1, wherein the height of said upper foam core section is less than the height of said lower foam core section, wherein the height is measured along an axis of the paddle portion perpendicular to said top edge and said bottom edge of said paddle portion at a position wherein said upper foam core section is located along said top edge and wherein said lower foam core section is located along said bottom edge.
 9. The hockey stick blade of claim 1, wherein the height of said upper foam core section is greater than the height of said lower foam core section, wherein the height is measured along an axis of the paddle portion perpendicular to said top edge and said bottom edge of said paddle portion at a position wherein said upper foam core section is located along said top edge and wherein said lower foam core section is located along said bottom edge.
 10. The hockey stick blade of claim 3, wherein at least one of said upper foam core section and said lower foam core section includes a plurality of chopped reinforcing fibers.
 11. The hockey stick blade of claim 10, wherein said plurality of chopped reinforcing fibers comprises approximately five weight percent of at least one of said upper foam core section and said lower foam core section.
 12. The hockey stick blade of claim 11, wherein said plurality of chopped reinforcing fibers comprises a plurality of milled carbon fibers.
 13. The hockey stick blade of claim 1, wherein the hockey stick blade comprises a replaceable hockey stick blade.
 14. The hockey stick blade of claim 1, wherein the hockey stick blade is integrally formed with a hockey stick shaft to form a composite hockey stick. 15.-22. (canceled)
 23. A replacement hockey stick blade formed in accordance with the method of claim
 15. 24. A hockey stick having a hockey stick blade formed in accordance with the method of claim
 15. 